The present invention relates to a clamping band manufacturing machine and a method of manufacturing a clamping band, more precisely relates to a machine and a method for full-automatically manufacturing a clamping band.
Clamping bands have used to clamp rubber boots of vehicles, etc. Conventionally, the clamping bands are used to clamp relatively soft materials, e.g., rubber. These days, the clamping bands are used to clamp hard materials, e.g., hard plastics.
A front view of a clamping band having a plate is shown in FIG. 21. The clamping band comprises a band section 10, a clasp 12, a lever 14 and a plate 16. The band section 10 is made of a metal, formed into a circular-shape and both end portions are overlapped. The lever 14 is fixed to the overlapped portion by welding. The lever 14 is welded at a position xe2x80x9cXxe2x80x9d. The lever 14 is turned from a position shown in FIG. 21 to an outer face of the band section 10. By turning the lever 14 until reaching the outer face of the band section 10, an article (not shown) to be clamped is fully clamped by action of lever, then the lever 14 is fixed on the outer face of the band section 10 by the clasp 12. Therefore, a great clamping force is required, so the lever 14 is made of a proper material having enough durability. Further, the lever 14 must be laid along the outer face of the band section 10, so it is formed into an arc-shape.
The clasp 12 is bent to cover the lever 14, which has been fully turned to clamp the article, so as to hold the lever 14 on the outer face of the band section 10. The clasp 12 is welded to the band section 10 at a position xe2x80x9cYxe2x80x9d. The plate 16 is positioned by sliding along an inner face of the band section 10 until one end of the plate contacts an end of the clasp 12, so that the other end of the plate 16 is extended beyond the overlapped portion of the band section 10. The plate 16 is welded to the band section 10 at a position xe2x80x9cZxe2x80x9d. Reinforcing portions 16a are respectively formed along side edges of the plate 16 so as to reinforce the plate 16. The plate 16 closes a space formed by the overlapped portion of the band section 10 before clamping the article; the plate 16 covers a step portion, which is formed when a part of the band section 10 is moved and located under another part thereof by turning down the lever 14 so as to clamp the article. By employing the plate 16, the article can be wholly clamped with even force.
In the case of clamping hard materials, it is important to control inner diameter of the band section in a clamping state. The inner diameter in the clamping state is defined by length of the band section and length of the overlapped portion of the band section and the lever, so they must be correctly controlled. The lever, the clasp and the plate are fixed to the band section by welding, so welding accuracy also highly influence reliability of the clamping band. If the parts are not fully welded, they will be peeled off from the band section while claming an article. Further, if over current passes and sparks while welding, sharp flashes are formed near the welded positions and they make the clamping band dangerous.
Therefore, the clamping band must be manufactured with fully considering the above described points. The clamping band is manufactured by the steps of: welding the clasp to the band section; overlapping both end portions of the band section and welding them each other; welding the lever to the end portion of the band section; forming the band section into a circular loop; and welding the plate to the inner face of the band section. Namely, many actions, e.g., forming the band sections by cutting a long band-shaped material, forming the clasps, welding the parts, are combined, so the manufacturing steps cannot be full-automatically executed by conventional machines. Two or three steps or actions are executed in one machine, then work pieces must be transferred to another machine for next steps or actions.
Since the clamping bands are manufactured by a plurality of machines, the work pieces must be transferred. So manufacturing efficiency cannot be increased. And, it is difficult manufacture the clamping band having higher accuracy without producing bad products.
The present invention is invented to solve the above described disadvantages.
An object of the present invention is to provide a clamping band manufacturing machine and a method of manufacturing the clamping band, which are capable of full-automatically manufacturing the clamping bands, highly increasing the manufacturing efficiency, and improving the accuracy of the clamping bands without variation.
To achieve the object, the present invention has following structures.
The clamping band manufacturing machine of the present invention comprises:
a main machine part including:
a band shaping stage for forming a clasp material into a U-shape, welding the U-shaped clasp on a band section made by cutting a long band-shaped material with a prescribed length, bending a mid portion of the band section in an arc by a guide rod, and overlapping both end portions of the band section;
a lever welding stage for welding a lever material on the overlapped portion of the band section so as to extend the lever material from the overlapped ends;
an examination stage for measuring a length of an overlapped portion of the band section and the lever material;
an arc shaping stage for bending the lever material in an arc by a fixed die and a shaping die;
a circular shaping stage for expanding the bent portion of the band section so as to form the band section into a circular loop; and
a conveying mechanism synchronously conveying the work piece including the band section to each of the sages, which are serially arranged, with machining action of each of the stages; and
feeding mechanisms for feeding the band-shaped material, the clasp material and the lever material to the main machine part.
In the clamping band manufacturing machine of the present invention, the clamping bands can be full-automatically manufactured, so that the manufacturing efficiency can be highly increased and mass production of the reliable clamping bands can be easily realized.
In the clamping band manufacturing machine, the main machine part may further include a plate welding stage for making one end of a plate, which is bend in arc with curvature corresponding to that of the loop-shaped portion of the band section and which has reinforcing portions formed along both side edges, contact with an end of the clasp so as to position the plate on the loop-shaped portion of the band section and welding the plate thereon. With this structure, the clamping band can be manufactured easily.
In the clamping band manufacturing machine, the circular shaping stage may include:
a bending section for bending the band section at a position near the overlapped portion of the band section and the lever so as to leave the band section away from a front end of the lever;
an expanding section for pressing an outer face of the band section, whose end portions have been overlapped, so as to expand the looped portion of the band section;
a circular shaping section for inserting a bunch of wires into the expanded looped portion of the band section and inserting a columnar shaft into the bunch of the wires so as to shape the looped portion into a circular loop shape; and
a finishing section for inserting splitable dies into the circular looped portion of the band section and expanding the same by the splitable dies so as to form into a prescribed circle. With this structure, the band section can be formed into the circular loop with higher accuracy.
In the clamping band manufacturing machine, the arc shaping stage may include:
a fixed die;
a first shaping die for pressing the overlapped portion of the band section and the lever material with the fixed die so as to bend the overlapped portion in an arc; and
a second shaping die for pressing the lever material with the fixed die so as to bend the lever material in an arc, the second die being provided near the first shaping die. With this structure, the lever can be formed in the arc with higher accuracy, so buckle of the lever during clamping operation can be prevented and the lever can be securely fixed on the band section in the clamping state.
In the clamping band manufacturing machine, the band welding stage and the lever welding stage may respectively have sensors for detecting sparks, which generate while welding, and discharge the work piece, which is machined when the spark is detected, as a bad product.
In the clamping band manufacturing machine, each of the band shaping stage and the lever welding stage may include a pair of welding rods for pinching and holding welding portion and applying electric current for welding, and
the welding rods may be automatically exchanged when they are used predetermined times.
In the clamping band manufacturing machine, the examination stage may include a CCD camera for measuring the length of the overlapped portion of the band section and discharge the work piece, whose length of the overlapped portion is out of an allowable range.
Successively, the method of manufacturing a clamping band, which includes a loop-shaped band section having an overlapped portion, a lever being welded to the band section and a clasp being welded to the band section and capable of holding the lever turned to clamp an article to be clamped, of the present invention comprises the steps of:
forming the band section into a loop-shape;
bending the band section at a position near an overlapped portion of the band section and the lever so as to leave the band section away from a front end of the lever;
pressing an outer face of the band section, whose end portions have been overlapped, by a jig so as to expand the looped portion of the band section;
inserting a bunch of wires into the expanded looped portion of the band section;
inserting a columnar shaft into the bunch of the wires so as to shape the looped portion into a circular loop shape; and
inserting a splitable die into the circular looped portion of the band section and expanding the same by the splitable die so as to form into a prescribed circle.
By employing the method of the present invention, the clamping band, in which the band section is formed into a desired circular shape, can be easily manufactured.